The present application is the national stage under 35 U.S.C. 371 of PCT/EP99/04395, filed Jun. 24, 1999.
The present invention comprises a device for the application of hot-melt adhesive onto materials such as foils, paper, laminates, veneers, etc., with a housing that includes an adhesive feeder element and adjustable nozzle slot to let out the adhesive, whereby the applicator device forms a so-called slot nozzle.
In known applicator devices of this kind, the housing has a nozzle slot across almost its whole width whose application width can be changed by means of various masks made of metal sheets. Depending on the width of the desired or required nozzle slot, the respective mask has to be exchanged which requires the applicator device to be dismantled, which is awkward and time-consuming.
During a production stop, air can enter the device and harden the adhesive because the nozzle slot is open. In order to avoid this, the nozzle slot is generally taped closed by hand which is often not sufficient and the adhesive hardens anyway, which requires extensive cleaning of the device.
The object of the invention is to avoid the above drawbacks by designing the nozzle slot of the adhesive applicator device in such a way that it is easily and individually adjustable to the respective application width without the applicator device having to be dismantled, so that during a production stop the nozzle slot can be closed, thereby protecting the adhesive from any exterior influence.
This object of the invention is solved by the characteristic features of claim 1 of this patent.
In addition, the adhesive must be protected against hardening by means of an advantageous route from the feeder element to the exit from the nozzle slot.
This object of the invention is solved by the characteristic features of claims 12 and 13 of this patent.
Furthermore, the width of the nozzle slot must be easily manually or automatically adjustable according to the width or the shape of the work piece.
These objects are solved by claims 14 and 15.
Advantageous further embodiments of the solutions are contained in the rest of the subclaims.
In the present device for the application of hot-melt adhesive, the characteristic features of the invention provide the following advantages:
1. The application width of the nozzle slot of the applicator device can be continuously and individually adjusted from a minimum (zero) to a maximum opening position by means of nozzle sliders, whereby this adjustment can be carried out without any dismantling of the applicator device. The sliders are manually displaced by means of threaded spindles.
2. The size of the displacement of the sliders can be selected either through synchronous displacement from the zero position to both sides or through separate displacement, whereby the application width for the respective work piece can be individually set, i.e. application can be right in the middle, just on one side or more on one side than the other.
3. The nozzle sliders are formed by strips that are V-shaped in profile and that have tongues or tongue-shaped swords arranged at the longitudinal ends facing the zero position, and these V-shaped slider strips with tongues are positioned in respective slider guides and the slider slot, and because the adhesive is to be applied by means of pressure, the slider strips with the tongues (swords) are firmly pressed to the opposing surfaces of the slider guides and the nozzle slot, so that in any nozzle width setting as well as in the closed position, the slot nozzle (whose tongues (swords) on the longitudinal ends lie adjacent to each other when in the zero position) is sealed securely against the exterior.
4. This tight guide mechanism and the tight closure of the slides in the zero position results in a closed adhesive application system, so that when the device is stopped the adhesive cannot be affected from the exterior (e.g. by air) and, therefore, cannot harden.
5. The adhesive feeder element in the device has been advantageously designed in that the movement of the hot-melt adhesive is constant from its entry to its exit, whereby there are no dead corners in which the adhesive could harden.
6. The whole device is simply and inexpensively constructed from a few components, is easy to install, does not require constant maintenance due to the adjustable nozzle slot and the guide mechanism, and can be used for the horizontal or vertical application of adhesive to the various moving materials.
7. The width of the nozzle slot is easily and manually continuously adjustable to the width of the work piece by means of threaded spindles and linear guides.
8. The adjustment of the nozzle width also depends on the width of the work piece moving through and the direction of the movement (straight, diagonal, zig-zag), and can be carried out electronically by means of sensors;
9. A distance pick-up senses the respective width of the work piece moving through and controls an adhesive dosing apparatus for precise adhesive application.